Radiation sensitive smoke detecting device



w. MOORE 3,505,529

RADIATION SENSITIVE SMOKE DETECTING DEVICE April 7, 1970 Filed Feb. 8. 1968 M i L A 4\ G 5 H RAIZ E l w i 2+ M INVENTOR. Wl LCY MOOR E ATTORNEYS.

United States Patent 3,505,529 RADIATION SENSITIVE SMOKE DETECTING DEVICE Wiley Moore, Folsom, Pa., assignor to E. W. Bliss Company, Canton, Ohio, a corporation of Delaware Filed Feb. 8, 1968, Ser. No. 703,950 Int. Cl. G01n 21/26 US. Cl. 250-218 4 Claims ABSTRACT OF THE DISCLOSURE There is provided an improvement in smoke detecting devices of the type adapted to be mounted in a room and permitting air flow therethrough, such devices having smoke detecting and signalling means associated therewith and actuated by smoke particles carried into the device with the air flow. This improvement includes a device having a porous body portion with a cavity therein and a plurality of recesses extending outwardly from the cavity. A lamp is disposed in one of the recesses and means are provided for emitting light rays across the cavity. A normally non-illuminated photo-electric cell is mounted in another of the recesses and shielded from the light rays emitted by the lamp. The porous body portion permits air flow through the walls thereof, and when smoke is carried into the cavity, light rays are reflected from the smoke particles to actuate the photo-electric cell and subsequently activate an alarm of some suitable nature.

The present invention pertains to the art of smoke detecting devices, and more particularly to a device for detecting and announcing the presence of smoke particles in air flowing through the device.

The present invention is particularly applicable for use in detecting the presence of smoke, and it will be described with particular reference thereto; however, it is to be appreciated that the invention has much broader applications and may be used in various other installations to detect and announce the presence of other air carried particles wherein detection and announcement of such particles is required.

Smoke detecting devices have been used for many years in various locations as a means for detecting a dangerous condition, such as an actual fire or a smoldering combustion which could lead to a dangerous fire. It is often the case that something will smolder, giving off quantities of smoke before sufficient heat is generated to set off a heat responsive fire alarm or fire protection system. Such smoke detecting devices are usually mounted in or on a ceiling of a room and positioned so that through either normal or generated air flow, any smoke in the room will be carried through the device. Some suitable means are provided to detect the presence of smoke in the device, thus triggering an alarm or protection system. Most such devices are light responsive; that is, the detecting and announcing of the presence of smoke is triggered in accordance with the action of light rays within the device as interfered with by the smoke particles carried in the air.

Devices of this nature used in the past have taken advantage of photo-electric cells as the actuating means for the alarm system. Some sort of light emitting means is disposed in the device so that light rays reflected from particles of smoke carried into the devices actuate the "ice cell and thus create the signal. Numerous problems are, however, presented with devices known in the past. Generally speaking, the air flow into the device, which carries therewith any smoke particles present, is through a tortuous path provided by openings disposed in fixed locations in the device and flow is only through such openings. Secondly, such openings must be very carefully protected against the entry of dirt, dust and other foreign materials, as well as flying insects, to prevent a triggering of the photo-electric cell by means other than the smoke particles desired. Another problem has been in illumination of the photo-electric cell in the absence of smoke particles, due to the light rays reflecting from surface within the device and finding their way to the cell. To overcome these problems, it has been necessary to utilize a complicated and cumbersome mechanism, requiring numerous pieces which must be assembled in a precise and accurate manner, such devices being generally unsightly because of the necessary construction and expensive to manufacture and produce. Accordingly, there has been an everpresent demand for a smoke detecting device that would allow a substantial reduction in the materials required for the device, a substantial reduction in the cost of manufacture and assembly of such a device, and a structure that may be esthetically formed to be more pleasing in appearance.

The present invention is directed toward a smoke detecting device that is substantially less expensive than known devices, contains relatively few parts, is easily manufactured and produced on a production basis, is easily and passed through a porous supporting body of the device for detection therein.

In accordance with another aspect of the present invention, there is provided a smoke detecting device having an internal cavity and recess arrangement for ease in mounting and actuating the smoke detecting and alarm equipment.

In accordance with still a further aspect of the present invention, there is provided a smoke detecting device which is easily formed and is adaptable to all shapes and sizes, depending on the desires of the user.

The primary object of the present invention is the provision of a smoke detecting device comprising a porous body portion permitting air flow therethrough, and internally formed to receive and mount light sensitive smoke detecting and announcing means.

Another object of the present invention is the provision of a smoke detecting device comprising a porous body portion having a cavity and recess arrangement therein, lamp means mounted in the cavity and recess arrangement, and detecting means, a portion of which is a photoelectric cell, mounted in the porous body portion.

Still another object of the present invention is the provision of a smoke detecting device comprising a porous body having a cavity and recess arrangement therein, lamp means mounted in the body portion, detecting means mounted in the body portion, and means for shielding the detecting means from the lamp means to prevent actuation of the detecting means in the absence of smoke particles within the device.

These and other objects and advantages will become apparent from the following description used to illustrate a preferred embodiment of the present invention as read in connection with the accompanying drawings in which:

FIGURE 1 is a plan view, with parts broken away and in section, of a smoke detecting device constructed in accordance with the present invention;

FIGURE 2 is an elevational view, with parts broken away and in section, of the smoke detecting device illustrated in FIGURE 1; and

FIGURE 3 is a perspective view, with parts broken away and in section, of the body portion of the smoke detecting device illustrated in FIGURES; 1 and 2.

Referring now to the drawings, wherein the showings are for the purpose of illustrating a preferred embodimeht of the invention only and not for the purpose of limiting same, FIGURE 1 illustrates the basic structure in which the body portion, indicated generally by the numeral 10, has associated therewith, in a manner to become hereinafter more apparent, a signal-alarm system, indicated generally by the numeral 12. Body portion is shown to be frustoconical in shape, having an end Wall 14, a conical side Wall 16 and an upper end wall 18. End wall 18 may be mounted in any suitable manner, as by fastening devices, adhesives or the like, to a wall or ceiling structure 20, in an optimum location for operation thereof.

Body portion 10 is formed of a plastic inter-cellular foam materail of any of the well known types, such as articulated polyurethane foam. The open cell structure of the material permits air flow through the end walls 14 and 18, and the side walls 16 of the device, from any point and from any direction. The foam material may be molded in any suitable shape, the body portion 10 being shown as frusto-conical in the drawings for convenience only. Should the user desire some other shape for esthetic balance in the room in which the device is used, such other shape may be easily formed in the molding process of the body portion 10.

Extending downwardly from the upper wall 18 of the body portion 10 is a central cavity 22 into which the air flow through the foam material may easily pass. Such cavity 22 extends part way through the body portion 10 so as to provide a conveniently large space therein, but without disturbing the lower end wall 14. Flow is thus permitted through the wall 14 by means of the interconnected open cells of the material.

Extending radially outwardly from the cavity 22 are spaced recesses 24, 26, 28 and 30, which communicate with the central cavity 22. Recess 28 is diametrically opposite the cavity from recess 24, and recess 26 is disposed somewhat between recesses 28 and 24. The entire cavity and recess configuration is designed for easy formation in the molding of the body portion from the foam plastic material.

Mounted in any suitable manner within the body por tion 10 and extending into the recess 24 is a lamp, indicated generally by the numeral 32, the lamp 32 having suitable electrical connections 40 leading to an appropriate power source to illuminate the lamp. Also disposed in the recess 24, and in front of lamp 32, is a lens 42, the purpose for which is to direct light rays from the lamp 32 directly across the cavity 22 and into the recess 28 for purposes to become hereinafter more apparent. To assist in this function, a plate 44 having an aperture 46 is disposed in front of the lens 42, permitting only light passage through the aperture 46 as will become hereinafter more apparent.

Mounted in body portion 10 and extending into recess 26 is a photo-electric cell, indicated generally by the numeral 48, and of any type well known in the art. Photoelectric cell 48 is light sensitive; that is, upon receiving light rays a signal is passed through electrical connections 50 to an amplifier device 52 for amplification into useable parameters and electrical connector means 54 extend to a suitable alarm 56 in the manner well known in the art. The entire signal and alarm system, with the exception of the cell 48, may be disposed in any suitable location for the convenience of the user. At the same time, the amplifier and alarm means may be connected in some suitable manner to other like smoke detecting devices located elsewhere.

It is important that the actuating portion of photo-electric cell 48 be dispose-d deep within the recess 26 so as not to be activated by stray light rays from the lamp 32 in the absence of smoke particles in the cavity 22. The photo-electric cell 48 is normally non-illuminated so that when smoke appears in the cavity 22 and interferes with light rays passing from the lamp 32 and through the aperture 46, such light rays are reflected by the smoke particles to the cell 48, thus activating the signal system.

Recess 28, being disposed diametrically opposite recess 24, forms a light trap to assist in preventing illumination and activation of the cell 48 in the absence of smoke particles. The lens 42 and aperture plate 44 direct the light rays from the lamp 32 into the recess 28 where the light is trapped and absorbed so as not to activate the cell 48.

In the operation of the smoke detecting device, it will now be apparent that during normal conditions the lamp 32 is illuminated to emit light rays through the lens 42 and the aperture 46 toward the recess 28. So long as no foreign particles are present in the cavity 22, the photoelectric cell 48 and the amplifier and the alarm will be in a static condition. At such time as air flow through the porous celled body portion 10 conveys therewith smoke particles into the central cavity 22, the smoke particles will cause a reflection, or deflection, of light rays from the lamp 32 toward the cell 48. When the cell 48 is thus illuminated, a signal is created to the amplifier 52 setting off a suitable alarm from the device 56. When the smoke has disapeared, as by continuous air flow through the device, and assuming the smoke has cleared from the atmosphere surrounding the device, the cavity 22 will also clear and light will continue to be trapped and absorbed in the recess 28, thus removing the illumination of the photo-electric cell 48 and the signal to the amplifier and alarm.

Thus, a device is provided which is extremely simple to manufacture, produce and operate, and which may be conveniently shaped to suit the esthetic desires of the user. The body portion of the device, being of open celled foam construction, provides desirable air flow through the device from any direction, and at the same time provides a barrier against insects and the like from the interior of the structure. The interior configuration provides a simple and eifective means for light transmission and illumination of the activating means in the presence of smoke particles finding their way into the interior of the device with the air flow.

The present invention has been described in connection with certain structural embodiments; however, it is to be appreciated that various changes may be made in the structural embodiments without departing from the intended spirit and scope of the present invention as defined by the appended claims.

Having thus described my invention, 1 claim:

1. In a smoke detecting device of the type including housing means having a cavity therein with the housing wall around the cavity being porous to permit flow of air and smoke particles therethrough, and light emitting means and signal emitting means positioned in said cavity so that said light emitting means illuminates at least a portion of the cavity and said signal emitting means being responsive to light reflected from particles of smoke in the cavity to actuate a signal device, the improvement comprising; said housing being formed in one integral piece of open-cell foam material and said porous wall being defined by said foam material.

2. The device of claim 1 wherein said housing includes References Cited a bottom wall and a continuous sidewall extending up- UNITED STATES PATENTS wardly from said bottom wall, said cavity belng defined by said bottom wall and said sidewall, said bottom wall 2,306,588 12/1942 cahusac et a1 356-207 X and said sidewall being porous to permit flow of air and 5 2,468,740 5/1949 Else 356-2O7 X smoke particles therethrough into said cavity. 3,327,126 6/1967 Shannon et a1 250 238 3. The device of claim 2 wherein at least one of said 3,361,030 1/1968 Goldberg 250218 X light emitting means and said signal emitting means is 33831670 5/1968 Roberts 34O 2377 mounted on said sidewall within said cavity.

4. The device of claim 2 wherein said light emitting 10 WALTER STOLWEIN Primary Examiner means and signal emitting means are mounted on said US. Cl. X.R. sidewall within said cavity. 340237; 356-207 

